Sealed system including a reheat coil and secondary expansion valve with heat pump bypass

ABSTRACT

An air conditioner unit includes a sealed system having an outdoor heat exchanger, a reheat heat exchanger, and an indoor heat exchanger in serial flow communication with each other. A first expansion device is positioned between the outdoor heat exchanger and the reheat heat exchanger and a second expansion device is positioned between the reheat heat exchanger and the indoor heat exchanger. A bypass loop routes the flow of refrigerant around the second expansion device when the flow of refrigerant is passing from the indoor heat exchanger to the reheat heat exchanger (i.e., in a heat pump mode), but directs that flow of refrigerant through the second expansion device when the flow of refrigerant is passing from the reheat heat exchanger to the indoor heat exchanger (i.e., in an air conditioning mode).

FIELD OF THE INVENTION

The present subject matter relates generally to air conditioner units, and more particularly to improved sealed system configurations for use in air conditioner units.

BACKGROUND OF THE INVENTION

Air conditioning systems are conventionally utilized to condition air within an indoor space—i.e., to adjust the temperature and humidity of the air within structures such as dwellings and office buildings. Such systems commonly include a closed refrigeration loop to condition the indoor air which is recirculated while being heated or cooled. Certain refrigeration loops include an outdoor heat exchanger positioned outdoors, an indoor heat exchanger positioned indoors, and tubing or conduit for circulating a flow of refrigerant through the heat exchangers to facilitate heat transfer.

When the air within the indoor space is humid, it may be desirable to remove moisture from the air. Air conditioning systems typically dehumidify air by passing the humid air over an indoor heat exchanger that has cool refrigerant passing through its coils. As the humid air passes through the indoor heat exchanger and crosses over its refrigerant cooled coils, the coils pull moisture from the air by lowering the temperature of the air and causing moisture in the air to condense on the coils. The dehumidified air is then passed into the indoor space at a lower temperature and humidity.

However, in certain situations, such as when the dehumidified air is below the indoor target temperature, it may be desirable to reheat the dehumidified air. Certain air conditioning systems use electric heaters to heat the indoor air downstream of the indoor heat exchanger. However, such electric heaters are costly and decrease the energy efficiency of the air conditioning system. By contrast, a reheat heat exchanger may be used, which can be throttled to pass hot refrigerant through its coils to reheat the overcooled air. However, conventional implementations including reheat heat exchangers suffer detrimental effects when operating in a heating mode of operation.

Accordingly, improved air conditioning systems with features for removing humidity in high humidity environments in an AC mode while facilitating improved heat capacity in a heat pump mode of operation would be useful.

BRIEF DESCRIPTION OF THE INVENTION

Aspects and advantages of the invention will be set forth in part in the following description, may be obvious from the description, or may be learned through practice of the invention.

In accordance with one embodiment, a sealed system for an air conditioner unit is provided. The sealed system includes a refrigeration loop including an outdoor heat exchanger, a reheat heat exchanger, and an indoor heat exchanger in serial flow communication with each other. A compressor is operably coupled to the refrigeration loop and is configured for circulating a flow of refrigerant through the refrigerant loop. A first expansion device is operably coupled to the refrigeration loop between the outdoor heat exchanger and the reheat heat exchanger and a second expansion device is operably coupled to the refrigeration loop between the reheat heat exchanger and the indoor heat exchanger. A bypass loop routes the flow of refrigerant around the second expansion device when the flow of refrigerant is passing from the indoor heat exchanger to the reheat heat exchanger.

In accordance with another embodiment, an air conditioner unit is provided. The air conditioner unit includes a partition defining an indoor portion and an outdoor portion, an outdoor heat exchanger positioned within the outdoor portion, and a reheat heat exchanger and an indoor heat exchanger positioned within the indoor portion. An outdoor fan urges a flow of outdoor air through the outdoor heat exchanger and an indoor fan urges a flow of indoor air through the indoor heat exchanger and the reheat heat exchanger. A first expansion device provides fluid communication between the outdoor heat exchanger and the reheat heat exchanger and a second expansion device provides fluid communication between the reheat heat exchanger and the indoor heat exchanger. A bypass loop routes a flow of refrigerant around the second expansion device when the flow of refrigerant is passing from the indoor heat exchanger to the reheat heat exchanger.

These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures.

FIG. 1 provides a schematic view of an exemplary air conditioner unit and sealed system in accordance with one exemplary embodiment of the present disclosure.

FIG. 2 provides a detailed schematic view or circuit diagram of the exemplary sealed system of FIG. 1 operating in an air conditioning mode according to an exemplary embodiment of the present subject matter.

FIG. 3 provides a detailed schematic view or circuit diagram of the exemplary sealed system of FIG. 1 operating in a heating mode according to an exemplary embodiment of the present subject matter.

FIG. 4 provides a pressure-enthalpy diagram of a sealed system operating in an AC mode according to an exemplary embodiment of the present subject matter.

FIG. 5 provides a pressure-enthalpy diagram of a sealed system operating in a typical hot gas reheat mode according to an exemplary embodiment of the present subject matter.

FIG. 6 provides a pressure-enthalpy diagram for the exemplary sealed system of FIG. 1 operating in an enhanced latent energy percentage mode according to an exemplary embodiment of the present subject matter.

Repeat use of reference characters in the present specification and drawings is intended to represent the same or analogous features or elements of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents.

As used herein, the terms “first,” “second,” and “third” may be used interchangeably to distinguish one component from another and are not intended to signify location or importance of the individual components. The terms “upstream” and “downstream” refer to the relative direction with respect to fluid flow in a fluid pathway. For example, “upstream” refers to the direction from which the fluid flows and “downstream” refers to the direction to which the fluid flows. In addition, terms of approximation, such as “approximately,” “substantially,” or “about,” refer to being within a ten percent margin of error.

Referring now to FIG. 1, an air conditioning system 10 is provided. The system 10 includes an indoor portion 12 and an outdoor portion 14 separated by a partition 16, such as a wall, a bulkhead, or the like. Although indoor portion 12 and outdoor portion 14 are illustrated as being adjacent to each other and separated by partition 16, it should be appreciated that this is only one exemplary embodiment. According to alternative embodiments, indoor portion 12 and outdoor portion 14 may be positioned separate from each other and connected by extended lengths of tubing or conduit.

Indoor portion 12 of air conditioning system 10 may generally define an indoor air duct 20 through which indoor air may be circulated for conditioning. More specifically, indoor air duct 20 may define an indoor return vent 22 for drawing a flow of indoor air into system 10 and an indoor supply vent 24 positioned downstream of indoor return vent 22 for supplying conditioned indoor air back into the room.

Similarly, outdoor portion 14 of air conditioning system 10 may generally define an outdoor air duct 30 through which outdoor air may be passed, e.g., for discharging thermal energy to, or absorbing thermal energy from, the ambient environment. More specifically, outdoor air duct 30 may define an inlet 32 for drawing a flow of ambient air into system 10 and an outlet 34 positioned downstream of inlet 32 for discharging outdoor air from system 10.

Air conditioning system 10 includes an indoor heat exchanger 40 and a reheat heat exchanger 42 which are positioned within indoor duct 20 between indoor return vent 22 and indoor supply vent 24. In addition, an indoor fan 44 is in fluid communication with indoor duct 20 for urging a flow of indoor air (identified herein by reference numeral 46) through indoor heat exchanger 40 and reheat heat exchanger 42. According to the illustrated embodiment, indoor fan 44 is positioned upstream of indoor heat exchanger 40 and reheat heat exchanger 42, e.g., proximate indoor return vent 22. In addition, reheat heat exchanger 42 is positioned downstream of indoor heat exchanger 40 relative to the flow of indoor air 46. According to exemplary embodiment, reheat heat exchanger 42 and indoor heat exchanger 40 are joined in a single coil bank, or are otherwise positioned immediately adjacent each other.

In addition, air conditioning system 10 includes an outdoor heat exchanger 50 which is positioned within outdoor duct 30 between inlet 32 and outlet 34. An outdoor fan 52 is in fluid communication with outdoor duct 30 for urging a flow of outdoor air (identified herein by reference numeral 54) through outdoor heat exchanger 50. According to the illustrated embodiment, outdoor fan 52 is positioned upstream of outdoor heat exchanger 50, e.g., proximate inlet 32, though other positions and configurations are possible and within the scope of the present subject matter.

Heat exchangers 40, 42, and 50 may be components of a refrigeration loop 60, which is shown schematically in FIG. 1. Refrigeration loop 60 may include, for example, various lines or conduit 62 that fluidly couple heat exchangers 40, 42, and 50 in a serial flow relationship. Conduit 62 facilitates the flow of refrigerant between the various components of refrigeration loop 60, thus providing the fluid communication there between. Refrigeration loop 60 may further include a compressor 64 for urging or circulating the refrigerant throughout the sealed system. Compressor 64 may include a reversing valve (not shown) or other suitable device for reversing the direction of the flow of refrigerant within refrigeration loop 60, e.g., to switch between an air conditioning and heating mode of operation.

According to an example embodiment, compressor 64 may be a variable speed compressor. In this regard, compressor 64 may be operated at various speeds depending on the current air conditioning needs of the room and the demand from refrigeration loop 60. For example, according to an exemplary embodiment, compressor 64 may be configured to operate at any speed between a minimum speed, e.g., 1500 revolutions per minute (RPM), to a maximum rated speed, e.g., 3500 RPM. Notably, use of variable speed compressor 64 enables efficient operation of refrigeration loop 60 (and thus air conditioning system 10), minimizes unnecessary noise when compressor 64 does not need to operate at full speed, and ensures a comfortable environment within the room.

According to the illustrated embodiment, refrigeration loop 60 further includes a first expansion device 66 that is operably coupled to refrigeration loop 60 and is positioned between outdoor heat exchanger 50 and reheat heat exchanger 42. In addition, refrigeration loop 60 includes a second expansion device 68 that is operably coupled to refrigeration loop 60 and is positioned between the reheat heat exchanger 42 and indoor heat exchanger 40. Notably, by including second expansion device 68 between reheat heat exchanger 42 and indoor heat exchanger 40, during an air conditioning mode of operation, the latent heat extraction is maximized with minimal impact on overall cooling capacity. However, under certain conditions, the inclusion of a secondary expansion valve between a reheat and indoor coil may result in deteriorated heat pump performance of an air conditioner unit. Thus, aspects of the present subject matter are directed to facilitating such an improved AC mode of operation while still allowing maximum heat capacity of refrigeration loop 60 in a heat pump mode of operation.

Specifically, refrigeration loop 60 may further include a bypass loop 70 which is generally configured for routing the flow of refrigerant around the second expansion device 68 when that flow of refrigerant is passing from indoor heat exchanger 42 reheat heat exchanger 42 (e.g., as indicated by solid lines in FIG. 3). According to the illustrated embodiment, bypass loop 70 includes a bypass conduit 72 that is coupled to conduit 62 immediately upstream and downstream of second expansion device 68. In other words, bypass conduit 72 is fluidly coupled in parallel with second expansion device 68.

In addition, bypass loop 70 includes a one-way valve or check valve 74 that is operably coupled to bypass conduit 72 to prevent the flow of refrigerant from passing through the bypass conduit 72 when that refrigerator is flowing from reheat heat exchanger 42 toward indoor heat exchanger 40 (e.g., as indicated by dotted lines in FIG. 2). Thus, when air conditioner unit 10 is operating in an AC mode (e.g., as shown in FIG. 2), check valve 74 is reversed biased to prevent the flow of refrigerant through bypass conduit 72, thus directing the flow of refrigerant through second expansion device 68. By contrast, when air conditioner unit 10 is operating in a heat pump mode (e.g., as shown in FIG. 3), check valve 74 is forward biased such that refrigerant may freely pass through check valve 74 through bypass conduit 72 toward reheat heat exchanger 42. Thus, in the heat pump mode, the flow of refrigerant does not pass through second expansion device 68, such that indoor heat exchanger 40 and reheat heat exchanger 42 act as a single coil bank heat exchanger (e.g., as if bypass loop 70 were replaced by a single open section of conduit 62).

Now that the configuration of air conditioner unit 10 has been generally described, exemplary modes of operation will be described with respect to FIGS. 2 and 3. Specifically, FIG. 2 illustrates an air conditioning mode of operation, while FIG. 3 illustrates a heat pump mode of operation. In general, the flow of refrigerant is illustrated by solid lines in these figures, whereas stagnant or unused portions of refrigeration loop 60 are illustrated by dotted lines. Although exemplary operation is described herein, it should be appreciated that air conditioner unit 10 and refrigeration loop 60 may be modified while remaining within the scope of the present subject matter.

Referring now specifically to FIG. 2, when compressor 64 is circulating refrigerant to facilitate an AC mode of operation, the flow of refrigerant is generally passing counterclockwise as shown in the figure from compressor 64 directly to outdoor heat exchanger 50. From outdoor heat exchanger 50, the refrigerant flows through first expansion device 66 and into reheat heat exchanger 42. After passing through reheat heat exchanger 42, the flow of refrigerant is prevented by check valve 74 from passing through bypass conduit 72, such that substantially the entire flow of refrigerant passes through second expansion device 68 before entering indoor heat exchanger 40. After leaving indoor heat exchanger 40, the flow of refrigerant recirculates through compressor 64, and the cycle continues. When refrigeration loop 60 is operating in an AC or cooling mode, and thus performing a refrigeration cycle, the indoor heat exchanger 40 and reheat heat exchanger 42 act as evaporators and the outdoor heat exchanger 50 acts as a condenser.

Referring now specifically to FIG. 3, when compressor 64 is circulating refrigerant to facilitate a heat pump mode of operation, the flow of refrigerant is generally passing clockwise as shown in the figure from compressor 64 directly to indoor heat exchanger 40. After exiting indoor heat exchanger 40, the flow of refrigerant passes through bypass conduit 72 of bypass loop 70 because check valve 74 is forward biased. Thus, in the heat pump mode of operation, second expansion device 68 does not act to expand the flow of refrigerant. Thus, the flow of refrigerant passes directly into reheat heat exchanger 42, which operates as an extension of indoor heat exchanger 40. After exiting reheat heat exchanger 42, the flow of refrigerant passes through first expansion device 66, into outdoor heat exchanger 50, and back to a compressor 64 for recirculation. When refrigeration loop 60 is operating in a heating mode, and thus performing a heat pump cycle, the indoor heat exchanger 40 and reheat heat exchanger 42 act as condensers and the outdoor heat exchanger 50 acts as an evaporator.

Heat exchangers 40, 42, 50 may each include coils through which a refrigerant may flow for heat exchange purposes, as is generally understood. It should be appreciated that the refrigerant may generally undergo phase changes associated with a refrigeration cycle as it flows to and through these various components, as is generally understood. Suitable refrigerants for use in refrigeration loop 60 may include pentafluoroethane, difluoromethane, or a mixture such as R410a, although it should be understood that the present disclosure is not limited to such example and rather that any suitable refrigerant may be utilized.

In exemplary embodiments as illustrated, expansion devices 66, 68 may be electronic expansion valves that enable controlled expansion of refrigerant, as is known in the art. More specifically, electronic expansion devices 66, 68 may be configured to precisely control the expansion of the refrigerant to maintain, for example, a desired temperature differential of the refrigerant across the indoor heat exchanger 40. According to alternative embodiments, expansion devices 66, 68 may be capillary tubes or another suitable expansion device configured for use in a thermodynamic cycle.

According to the illustrated exemplary embodiment, indoor fan 44 and outdoor fan 52 are illustrated as axial fans. However, it should be appreciated that according to alternative embodiments, indoor fan 44 and outdoor fan 52 may be any suitable fan type. For example, one or both of indoor fan 44 and outdoor fan 52 may be centrifugal fans. In addition, according to an exemplary embodiment, indoor fan 44 and outdoor fan 52 are variable speed fans and may rotate at different rotational speeds to generate different air flow rates. It may be desirable to operate indoor fan 44 and outdoor fan 52 at less than their maximum rated speed to ensure safe and proper operation of refrigeration loop 60 at less than its maximum rated speed, e.g., to reduce noise when full speed operation is not needed.

The operation of air conditioning system 10 including compressor 64 (and thus refrigeration loop 60 generally), indoor fan 44, outdoor fan 52, expansion devices 66, 68, and other components of refrigeration loop 60 may be controlled by a processing device such as a controller 80. Controller 80 may be in communication (via for example a suitable wired or wireless connection) to such components of the air conditioning system 10. By way of example, the controller 80 may include a memory and one or more processing devices such as microprocessors, CPUs or the like, such as general or special purpose microprocessors operable to execute programming instructions or micro-control code associated with operation of system 10. The memory may represent random access memory such as DRAM, or read only memory such as ROM or FLASH. In one embodiment, the processor executes programming instructions stored in memory. The memory may be a separate component from the processor or may be included onboard within the processor.

System 10 may additionally include a control panel 82 and one or more user inputs, which may be included in control panel 82. The user inputs may be in communication with the controller 80. A user of the system 10 may interact with the user inputs to operate the system 10, and user commands may be transmitted between the user inputs and controller 80 to facilitate operation of the system 10 based on such user commands. A display may additionally be provided in control panel 82, and may be in communication with the controller 80. The display may, for example be a touchscreen or other text-readable display screen, or alternatively may simply be a light that can be activated and deactivated as required to provide an indication of, for example, an event or setting for the system 10.

Air conditioning system 10 may further include one or more sensors used to facilitate operation of system 10. For example, sensors may be used for measuring the temperature, pressure, humidity, or other conditions at any suitable locations within system 10 or in the ambient environment. According to the illustrated embodiment, system 10 includes a temperature sensor 90 positioned within indoor portion 12 or within the room being conditioned. Temperature sensor 90 may be any suitable temperature sensor. For example, temperature sensor 90 may be a thermocouple, a thermistor, or a resistance temperature detector.

As illustrated, temperature sensor 90 is positioned downstream of indoor heat exchanger 40 and reheat heat exchanger 42. More specifically, for example, temperature sensor 90 may be positioned proximate indoor supply vent 24. However, it should be appreciated that according to alternative embodiments, temperature sensor 90 may be positioned at any location suitable for detecting the temperature of dehumidified and reheated air to be supplied to the room. In addition, air conditioning system 10 may include one or more humidity sensors 92. In this regard, for example, system 10 can be configured for performing a dehumidification operation when the humidity of the indoor air is above a predetermined threshold. In addition, outdoor fan 52 can be controlled in response to both a humidity measurement by humidity sensor 92 and a temperature measurement by temperature sensor 90. According to the illustrated embodiment, humidity sensor 92 is positioned proximate indoor return vent 22 for measuring the humidity of return air or room air. However, humidity sensor 92 may be positioned in different locations according to alternative embodiments.

It should be appreciated that air conditioning system 10 is described herein only for the purpose of explaining aspects of the present subject matter. For example, air conditioning system 10 is used herein to describe exemplary configurations of refrigeration loop 60, the position and functions of various heat exchangers 40, 42, 50, and the types of sensors 90, 92 used to facilitate control of system 10. It should be appreciated that aspects of the present subject matter may be used to operate air conditioning systems having different types of heat exchangers and various different or additional components. Thus, the exemplary components and methods described herein are used only to illustrate exemplary aspects of the present subject matter and are not intended to limit the scope of the present disclosure in any manner.

The air conditioner unit and refrigeration loop described above provide a versatile system capable of improved operation in both the heating and cooling modes with a relatively simple and inexpensive construction. By selectively adding the bypass loop around the secondary expansion device (e.g., capillary tube) between the indoor coil and reheat coil, the latent capacity removed during AC mode may be maximized while still allowing the use of maximum heat capacity of both coils during the heat pump mode.

Referring now to FIGS. 4 through 6, pressure-enthalpy diagrams for a given refrigerant within a sealed system will be described according to aspects of the present subject matter. Specifically, FIG. 4 provides a pressure-enthalpy diagram for a conventional sealed system operating in an air conditioning mode. FIG. 5 provides a pressure-enthalpy diagram for a hot gas reheat mode to dehumidify a flow of indoor air. FIG. 6 provides a pressure-enthalpy diagram for an enhanced latent energy mode as described herein and implemented for example by air conditioning system 10.

Specifically, FIG. 4 shows a pressure-enthalpy diagram (e.g., a Moeller diagram) for a typical AC cycle of a sealed system as the refrigerant passes through points or states 1 through 4. As shown, energy is dumped to the outdoors at the high pressure side of the diagram (e.g., between 3 and 4). By contrast, energy is pulled out of the room in the low pressure side (e.g., between 1 and 2, which may be indicative of the cooling capacity of the system). The saturated temperature that corresponds to the state 1 low pressure is established by the efficiency and capacity needs of the sealed system.

Referring now to FIG. 5, a typical HOT gas reheat cycle is described using a pressure-enthalpy diagram according to an exemplary embodiment. According to such a reheat cycle, the mass flow coming out of the compressor goes both into the outdoor condenser and into the indoor reheat auxiliary coil. A first valve (e.g., a proportional valve) is used to partition the flow in an attempt to balance the heat that must be added to the room to equal the heat being pulled from the room by the main indoor coils. Both the reheat coil and the outdoor condenser come back together and are expanded by a second expansion valve (EEV2) to a low pressure/low evaporative saturated temperature. The cooling capacity into the room should be effectively zero with the net effect that much of the energy extracted by the indoor coils will be latent and condense water.

Referring now to FIG. 6, the operation of air conditioner unit 10 will be described using a pressure-enthalpy diagram according to an exemplary embodiment. Notably, operation of air conditioner unit 10 effectively drops the latent percentage from ˜20% to 40-50% without significantly affecting the total cooling capacity or the efficiency. As shown, the first expansion device 66 only expands the mass flow out of the condenser (e.g., outdoor heat exchanger 50) to a point where it is a little over room temperature, e.g., as illustrated from state 4 to state 1. In other words, the refrigerant is initially throttled some after the outdoor heat exchanger 50 to drop the refrigerant temperature slightly above room temperature (e.g., 72 degrees Fahrenheit) at a point that balances the vent air to room temperature.

The refrigerant then passes through the reheat heat exchanger 42, which dumps that heat into the room via the same air flow that goes through the indoor main coils in front of it (i.e., the flow of indoor air 46). In other words, some sensible heat is dumped into the room which is equivalent to the latent energy added back in on the main evaporator coils that are now able to be expanded to a much lower temperature. That added energy into the room allows second expansion device 68 to start expanding the refrigerant at a point much further to the left and at lower enthalpies, e.g., as illustrated from state 1A to state 1B. This allows the final evaporative temperature to be considerably lower than a standard AC mode at a given capacity.

Between states 1A and 1B, the refrigerant is again throttled to turn the remaining vapor refrigerant to a liquid refrigerant at a lower temperature than otherwise possible. Thus, the lower heat extraction portion of the diagram (e.g., between states 1B and 2) is much wider than a typical AC cycle and greater in magnitude, but that is balanced against the heat being added into the room. It all comes out to the same capacity as with a standard AC, but at a lower final temperature. This lower temperature improves the latent energy removal.

This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims. 

What is claimed is:
 1. A sealed system for an air conditioner unit, the sealed system comprising: a refrigeration loop comprising an outdoor heat exchanger, a reheat heat exchanger, and an indoor heat exchanger in serial flow communication with each other; a compressor operably coupled to the refrigeration loop and being configured for circulating a flow of refrigerant through the refrigerant loop; a first expansion device operably coupled to the refrigeration loop between the outdoor heat exchanger and the reheat heat exchanger; a second expansion device operably coupled to the refrigeration loop between the reheat heat exchanger and the indoor heat exchanger; and a bypass loop that routes the flow of refrigerant around the second expansion device when the flow of refrigerant is passing from the indoor heat exchanger to the reheat heat exchanger.
 2. The sealed system of claim 1, wherein the bypass loop comprises: a bypass conduit directing the flow of refrigerant around the second expansion device; and a check valve operably coupled to the bypass conduit to prevent the flow of refrigerant from passing through the bypass conduit when passing from the reheat heat exchanger to the indoor heat exchanger.
 3. The sealed system of claim 2, wherein the flow of refrigerant passes freely through the check valve when passing from the indoor heat exchanger to the reheat heat exchanger.
 4. The sealed system of claim 2, wherein the bypass conduit is fluidly coupled in parallel to the second expansion device.
 5. The sealed system of claim 1, wherein at least one of the first expansion device or the second expansion device are electronic expansion valves.
 6. The sealed system of claim 1, wherein at least one of the first expansion device or the second expansion device are capillary tubes.
 7. The sealed system of claim 1, further comprising: a partition defining an indoor portion and an outdoor portion, wherein the outdoor heat exchanger is positioned within the outdoor portion and both the reheat heat exchanger and the indoor heat exchanger are positioned within the indoor portion.
 8. The sealed system of claim 1, further comprising: an indoor fan for urging a flow of indoor air through the indoor heat exchanger and the reheat heat exchanger; and an outdoor fan for urging a flow of outdoor air through the outdoor heat exchanger.
 9. The sealed system of claim 8, wherein the reheat heat exchanger is positioned downstream of the indoor heat exchanger relative to the flow of indoor air.
 10. The sealed system of claim 1, wherein the reheat heat exchanger and the indoor heat exchanger are joined in a single coil bank.
 11. An air conditioner unit comprising: a partition defining an indoor portion and an outdoor portion; an outdoor heat exchanger positioned within the outdoor portion; an outdoor fan for urging a flow of outdoor air through the outdoor heat exchanger; a reheat heat exchanger and an indoor heat exchanger positioned within the indoor portion; an indoor fan for urging a flow of indoor air through the indoor heat exchanger and the reheat heat exchanger; a first expansion device providing fluid communication between the outdoor heat exchanger and the reheat heat exchanger; a second expansion device providing fluid communication between the reheat heat exchanger and the indoor heat exchanger; and a bypass loop that routes a flow of refrigerant around the second expansion device when the flow of refrigerant is passing from the indoor heat exchanger to the reheat heat exchanger.
 12. The air conditioner unit of claim 11, wherein the bypass loop comprises: a bypass conduit directing the flow of refrigerant around the second expansion device; and a check valve operably coupled to the bypass conduit to prevent the flow of refrigerant from passing through the bypass conduit when passing from the reheat heat exchanger to the indoor heat exchanger.
 13. The air conditioner unit of claim 12, wherein the flow of refrigerant passes freely through the check valve when passing from the indoor heat exchanger to the reheat heat exchanger.
 14. The air conditioner unit of claim 12, wherein the bypass conduit is fluidly coupled in parallel to the second expansion device.
 15. The air conditioner unit of claim 11, wherein at least one of the first expansion device or the second expansion device are electronic expansion valves.
 16. The air conditioner unit of claim 11, wherein at least one of the first expansion device or the second expansion device are capillary tubes.
 17. The air conditioner unit of claim 11, wherein the reheat heat exchanger is positioned downstream of the indoor heat exchanger relative to the flow of indoor air.
 18. The air conditioner unit of claim 11, wherein the reheat heat exchanger and the indoor heat exchanger are joined in a single coil bank. 